Introduction of transition metal ions during the synthesis of mesoporous molecular sieve MCM-41 can affect the final morphology of the particles. Mn2+ ions were introduced to the synthesis of MCM-41 materials in the presence of cetylpyridinium bromide surfactant, and a novel pigtail-like morphology was observed in the synthesized solids. Such a morphology is distinct from the morphology of mesoporous nanotubes when Mn2+ was replaced by other cations such as V4+ and Ti4+, and that of pure siliceous sample. The mesochannels in the pigtail-like particles can be either parallel to the pigtail-axis or undulatory in the longitudinal direction. The mesochannels extended from the bulk particles grow along the pigtail-axis or grow spirally. When the spirality is high, the mesopores with a direction perpendicular to the pigtail-axis can be observed at the edges of the particles. (C) 2002 Elsevier Science B.V. All rights reserved.